Printing environments such as, for example, print shops require a variety of workflow plans in order to achieve maximum efficiency and output in producing and rendering documents, graphics, and so forth. A print shop can be a system wherein devices for formatting, printing, cutting, and binding are utilized to create a finished printed product such as a book or brochure. A “workflow plan” is essentially an ordered or partially ordered list of the actions needed to accomplish the desired finished product using the devices available.
When “lights out” workflow automation is desired in a print shop, the automated validation of a workflow plan against the capabilities of the devices and services of the print shop is necessary. Current device capability description languages describe what an individual device is capable of performing, but are not efficient in describing the relationships between individual devices (e.g., Imposition must come before Print for a printer that does not do on-board imposition), nor do they express adequately how the device will effect or alter the workflow plan. It should be noted that printing of books is performed by printing large sheets of paper which are formatted through a process called imposition, for later folding that will result in sequential pagination. One example of the inefficiency of current device capability description languages is when an imposition device that performs Booklet-Signature imposition, the imposition device may alter the input image size from, for example, 8.5×11 to 17×11. Such an effect is not often described by the capability description of the imposition device. For this reason, the current state of the art can only be effectively used to validate workflow plans for which every effect of each step in the workflow is known a priori at the start of workflow execution, which is not always realistic.
Additionally, many of the constraints and capabilities of a device are not often contained in a formal capability description file, but are instead only available from other sources (e.g., queue settings, implicit knowledge, etc.). There are also a variety of device capability description languages which can further complicate how individual devices communicate. Some languages, such as Xerox Capabilities (XCAP), describe or relate to the capabilities of a printer. Another common device capability description language is Job Definition Format (JDF) which describes the capabilities of a wide range of devices found in the print shop. All of these factors make it difficult to accurately validate a workflow plan in a print shop.
Workflow plans can be generated utilizing a number of different approaches. For example, workflow plans can be automatically generated using technology that converts a product description into a workflow plan. Workflow plans can also be manually created as part of the order entry process and planning process within a print shop. Finally, a workflow plan may be supplied by an external entity, such as when a print shop receives work that has been vended out from another print shop.
There are many device capability description languages used in the industry today. Based on the foregoing, it is believed that because the content of such prior device capability description languages is well defined, a more efficient and desirable approach could involve mechanical mapping to facts and operators in a rule-based system, or facts, predicates and operators in the context of an automated planning environment. It is also believed that such an automated planning environment could provide greater user flexibility by functioning to both validate and synthesize workflow plans where minimal details are provided by a user. A benefit of such a hybrid approach also gives users the impression that they are in control, reducing the initial technology resistance for early adopters. Such an approach is described in greater detail herein.